USB harddisk took too much current

this mornig I tried to connect an external 2,5" HDD which was running on a
USB2 Bridge from an external case on a USB3 Bridge from another case. (I
wanted to check whether I could switch HDD to standby with another USB Bridge)
Raspi did not start with USB3 Bridge plugged in and after disconnecting USB
device an rebboting the Raspi it also doesn't come up. No signal on HDMI
monitor. Red LED is lit up, green LED is flickering but it does not boot up
or power any USB devices.
Is there any fuse I can check?
Kind regrads 
Andreas Bockelmann
Reply to
Andreas Bockelmann
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ha scritto:
I would start trying with another SD card. Could be that the moment the USB3 bridge started the HD, it assorbed too mu ch current, the voltage dropped and the sd card got corrupted.
Bye Jack
Reply to
jack4747 schrieb:
Thanks for the hint. But I forgot to mention that even color test screen is not shown when powering in rasppi. I was able to boot up to get a ping to raspi (LAN), but trying to connect via ssh ended with reset connection. So tehre might be a problem with power distribution.
This evening I will try to locate (poly-)fuses and check their resitances.
Kind regards 
Andreas Bockelmann
Reply to
Andreas Bockelmann
Andreas Bockelmann wrote on 8/16/2017 4:48 AM:
Probably not the "fuse" since they don't blow, rather are self resetting. Have you checked the power wall wart? It likely can't power the USB drive, they require a lot of power when starting. I used a cell phone wall wart to power a rPi without a hard drive and it worked for a considerable time... until it blew. It would read the right voltage with no load and my cell phone would say it was charging from it, but the voltage would drop to about 3V and the phone wouldn't actually charge. Of course it wouldn't boot the rPi at all. I got a power pack with enough current capability and it works much better now even with accessories attached.

Rick C
Reply to
Dear all,
this evening I just gave my raspi a try to start up. First without any external devives, no with old hdd and old USB bridge. Seems that polyfuse needed some time to recover. My raspi is alive. Maybe the polyfuse was a bit nervous about the switching voltage regulator in the USB 3 circuit I was testing. Okay, don't touch a running system.
Thanks for your advices...
Kind regards Andreas
Reply to
Andreas Bockelmann

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